The Rab GTPase RabG3b functions in autophagy and contributes to tracheary element differentiation in Arabidopsis
The Rab GTPase RabG3b functions in autophagy and contributes to tracheary element differentiation in Arabidopsis
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DOI：
10.1111/j.1365-313x.2010.04315.x
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发表时间：
2010-10-01
期刊：
影响因子：
7.2
通讯作者：
Park, Ohkmae K.
中科院分区：
文献类型：
--
作者：
Kwon, Soon Il;Cho, Hong Joo;Park, Ohkmae K.
P>木质部的气管元件（TE）充当植物维管系统的导水血管。为了实现这一目标，TE 经历次生细胞壁增厚和细胞死亡，在此期间细胞内容物被完全去除。 TE 的细胞死亡是发育性程序性细胞死亡的典型例子，已被认为是自噬性的。然而，几乎没有提供 TE 分化过程中自噬的证据。本研究表明，小 GTP 结合蛋白 RabG3b 通过其自噬功能在 TE 分化中发挥作用。发现分化的野生型 TE 细胞在拟南芥培养系统中经历自噬。自噬和 TE 的形成均受到组成型活性突变体 (RabG3bCA) 过表达的显着刺激，并且在过表达显性失活突变体 (RabG3bDN) 或 RabG3b RNAi (RabG3bRNAi)、油菜素类固醇不敏感突变体 bri1-301 和自噬突变体 atg5-1 的转基因植物中受到抑制。综上所述，我们的结果表明自噬发生在 TE 分化过程中，而 RabG3b 作为自噬的一个组成部分，调节 TE 分化。
P>The tracheary elements (TEs) of the xylem serve as the water-conducting vessels of the plant vascular system. To achieve this, TEs undergo secondary cell wall thickening and cell death, during which the cell contents are completely removed. Cell death of TEs is a typical example of developmental programmed cell death that has been suggested to be autophagic. However, little evidence of autophagy in TE differentiation has been provided. The present study demonstrates that the small GTP binding protein RabG3b plays a role in TE differentiation through its function in autophagy. Differentiating wild type TE cells were found to undergo autophagy in an Arabidopsis culture system. Both autophagy and TE formation were significantly stimulated by overexpression of a constitutively active mutant (RabG3bCA), and were inhibited in transgenic plants overexpressing a dominant negative mutant (RabG3bDN) or RabG3b RNAi (RabG3bRNAi), a brassinosteroid insensitive mutant bri1-301, and an autophagy mutant atg5-1. Taken together, our results suggest that autophagy occurs during TE differentiation, and that RabG3b, as a component of autophagy, regulates TE differentiation.